SmogRank / Episodes / Norway

Southern Norway, January 2024

For 5 days, from 6 to 10 January 2024, 10 cities in Norway had PM2.5 at least twice their usual for the time of year. The worst reading was Fredrikstad, Østfold, Norway: 91.5 µg/m³ on 10 January, about 11× its usual 8.0.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached10in 1 country
Days56 to 10 January 2024
Worst day7 January9 cities counted
Furthest above usual11×Fredrikstad

Day by day

7 January 9 cities at twice their usual or more
KristiansandLillehammerNesttunÅsaneGothenburgPorsgrunnHamarDrammenGjøvikBergenSarpsborgLillestrømOsloMossFredrikstad
3 Jan45678910111213
Every measured city in the area, coloured by its PM2.5 that day; a dark ring marks a city at twice its usual or more. Bars: cities counted each day, coloured by their median level. Choose a day or press play; without JavaScript, the days link to that day's world ranking.

How it spread

LillestrømLillestrøm, 3 January: no readingLillestrøm, 4 January: 15.6 µg/m³, 1.6× usualLillestrøm, 5 January: 29.0 µg/m³, 3.0× usualLillestrøm, 6 January: 34.7 µg/m³, 3.6× usualLillestrøm, 7 January: 35.6 µg/m³, 3.7× usualLillestrøm, 8 January: 40.3 µg/m³, 4.2× usualLillestrøm, 9 January: 57.7 µg/m³, 6.0× usualLillestrøm, 10 January: 45.8 µg/m³, 4.8× usualLillestrøm, 11 January: 23.1 µg/m³, 2.4× usualLillestrøm, 12 January: 20.5 µg/m³, 2.1× usualLillestrøm, 13 January: 26.8 µg/m³, 2.8× usualFredrikstadFredrikstad, 3 January: no readingFredrikstad, 4 January: 11.1 µg/m³, 1.4× usualFredrikstad, 5 January: 26.7 µg/m³, 3.3× usualFredrikstad, 6 January: 52.4 µg/m³, 6.6× usualFredrikstad, 7 January: 49.3 µg/m³, 6.2× usualFredrikstad, 8 January: 61.7 µg/m³, 7.7× usualFredrikstad, 9 January: 77.3 µg/m³, 9.7× usualFredrikstad, 10 January: 91.5 µg/m³, 11× usualFredrikstad, 11 January: 58.7 µg/m³, 7.3× usualFredrikstad, 12 January: 74.6 µg/m³, 9.3× usualFredrikstad, 13 January: 46.6 µg/m³, 5.8× usualBergenBergen, 3 January: no readingBergen, 4 January: 22.6 µg/m³, 3.2× usualBergen, 5 January: 26.5 µg/m³, 3.8× usualBergen, 6 January: 30.4 µg/m³, 4.3× usualBergen, 7 January: 28.2 µg/m³, 4.0× usualBergen, 8 January: 31.2 µg/m³, 4.5× usualBergen, 9 January: 7.7 µg/m³, 1.1× usualBergen, 10 January: 7.3 µg/m³, 1.0× usualBergen, 11 January: 6.9 µg/m³, 1.0× usualBergen, 12 January: 7.7 µg/m³, 1.1× usualBergen, 13 January: 6.0 µg/m³, 0.9× usualPorsgrunnPorsgrunn, 3 January: no readingPorsgrunn, 4 January: 9.9 µg/m³, 0.8× usualPorsgrunn, 5 January: 19.8 µg/m³, 1.7× usualPorsgrunn, 6 January: 37.7 µg/m³, 3.1× usualPorsgrunn, 7 January: 41.4 µg/m³, 3.4× usualPorsgrunn, 8 January: 36.7 µg/m³, 3.1× usualPorsgrunn, 9 January: 42.2 µg/m³, 3.5× usualPorsgrunn, 10 January: 33.1 µg/m³, 2.8× usualPorsgrunn, 11 January: 17.8 µg/m³, 1.5× usualPorsgrunn, 12 January: 28.5 µg/m³, 2.4× usualPorsgrunn, 13 January: 33.3 µg/m³, 2.8× usualOsloOslo, 3 January: no readingOslo, 4 January: 7.2 µg/m³, 1.0× usualOslo, 5 January: 20.7 µg/m³, 2.8× usualOslo, 6 January: 35.3 µg/m³, 4.7× usualOslo, 7 January: 32.3 µg/m³, 4.3× usualOslo, 8 January: 36.8 µg/m³, 4.9× usualOslo, 9 January: 54.1 µg/m³, 7.2× usualOslo, 10 January: 42.8 µg/m³, 5.7× usualOslo, 11 January: 17.9 µg/m³, 2.4× usualOslo, 12 January: 23.0 µg/m³, 3.1× usualOslo, 13 January: 30.5 µg/m³, 4.1× usualMossMoss, 3 January: no readingMoss, 4 January: 4.6 µg/m³, 0.7× usualMoss, 5 January: 11.8 µg/m³, 1.7× usualMoss, 6 January: 32.5 µg/m³, 4.6× usualMoss, 7 January: 26.6 µg/m³, 3.8× usualMoss, 8 January: 31.9 µg/m³, 4.6× usualMoss, 9 January: 42.1 µg/m³, 6.0× usualMoss, 10 January: 52.8 µg/m³, 7.5× usualMoss, 11 January: 14.9 µg/m³, 2.1× usualMoss, 12 January: 29.6 µg/m³, 4.2× usualMoss, 13 January: 30.1 µg/m³, 4.3× usualSarpsborgSarpsborg, 3 January: no readingSarpsborg, 4 January: 5.5 µg/m³, 0.6× usualSarpsborg, 5 January: 14.2 µg/m³, 1.5× usualSarpsborg, 6 January: 29.7 µg/m³, 3.2× usualSarpsborg, 7 January: 31.4 µg/m³, 3.3× usualSarpsborg, 8 January: 37.5 µg/m³, 4.0× usualSarpsborg, 9 January: 52.2 µg/m³, 5.6× usualSarpsborg, 10 January: 55.4 µg/m³, 5.9× usualSarpsborg, 11 January: 66.6 µg/m³, 7.1× usualSarpsborg, 12 January: 43.4 µg/m³, 4.6× usualSarpsborg, 13 January: 41.2 µg/m³, 4.4× usualGjøvikGjøvik, 3 January: no readingGjøvik, 4 January: 11.0 µg/m³, 1.4× usualGjøvik, 5 January: 20.9 µg/m³, 2.7× usualGjøvik, 6 January: 25.1 µg/m³, 3.3× usualGjøvik, 7 January: 20.8 µg/m³, 2.7× usualGjøvik, 8 January: 25.9 µg/m³, 3.4× usualGjøvik, 9 January: 33.8 µg/m³, 4.4× usualGjøvik, 10 January: 11.7 µg/m³, 1.5× usualGjøvik, 11 January: 2.8 µg/m³, 0.4× usualGjøvik, 12 January: 9.0 µg/m³, 1.2× usualGjøvik, 13 January: 8.3 µg/m³, 1.1× usualDrammenDrammen, 3 January: no readingDrammen, 4 January: 12.7 µg/m³, 1.2× usualDrammen, 5 January: 8.9 µg/m³, 0.9× usualDrammen, 6 January: 17.4 µg/m³, 1.7× usualDrammen, 7 January: 39.7 µg/m³, 3.9× usualDrammen, 8 January: 18.7 µg/m³, 1.8× usualDrammen, 9 January: 19.7 µg/m³, 1.9× usualDrammen, 10 January: 16.2 µg/m³, 1.6× usualDrammen, 11 January: 20.0 µg/m³, 2.0× usualDrammen, 12 January: 35.7 µg/m³, 3.5× usualDrammen, 13 January: 45.1 µg/m³, 4.4× usualHamarHamar, 3 January: no readingHamar, 4 January: no readingHamar, 5 January: no readingHamar, 6 January: no readingHamar, 7 January: 28.8 µg/m³, 2.1× usualHamar, 8 January: 38.7 µg/m³, 2.8× usualHamar, 9 January: 52.4 µg/m³, 3.8× usualHamar, 10 January: 46.4 µg/m³, 3.4× usualHamar, 11 January: 18.1 µg/m³, 1.3× usualHamar, 12 January: 26.6 µg/m³, 1.9× usualHamar, 13 January: 22.1 µg/m³, 1.6× usual3 Jan5791113
Every counted city, in the order the episode reached them, 3 days before to 3 after. Each square is a day, coloured by that day's PM2.5; outlined: at twice the city's usual or more.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

Every city it reached

CityDaysHighestUsualAbove usual
FredrikstadØstfold, Norway5 91.510 January8.011×
MossØstfold, Norway5 52.810 January7.07.5×
OsloOslo, Norway5 54.19 January7.57.2×
SarpsborgØstfold, Norway5 66.611 January9.47.1×
LillestrømAkershus, Norway5 57.79 January9.66.0×
BergenVestland, Norway3 31.28 January7.04.5×
DrammenBuskerud, Norway1 45.113 January10.24.4×
GjøvikInnlandet, Norway3 33.89 January7.74.4×
HamarInnlandet, Norway4 52.49 January13.73.8×
PorsgrunnTelemark, Norway5 42.29 January12.03.5×

Daily means in µg/m³. Usual: the city's median for this time of year (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that.

Use this page

SmogRank, Southern Norway, January 2024: 10 cities with PM2.5 at twice their usual or more, 6 to 10 January 2024, smogrank.com/episodes/2024-01-southern-norway (accessed 3 October 2026).

Download top 10 (PNG)

You're welcome to reuse a single chart, image or figure with this citation and a link. Terms.

An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes. Values are each city's daily mean of its own monitors; causes are the usual kinds for a pattern like this, not a confirmed source.